The present invention relates to circuit switching and particularly to remotely controlled switching.
Present practice in the telephone industry for handling trunk and local line installations is to install multi-pair feeder cables from central offices to crossconnect boxes and pedestals from which local pairs fan out to the various customers. A crossconnect box accommodates a large number of twisted pairs utilized in a 2:1 ratio, i.e., twice as many pairs for local or distribution service as are used for feeder service. A typical box can have 600 feeder pairs and 1200 distribution pairs for a total of 1800 pairs. Pedestals typically contain provision for a lesser number of pairs, e.g., 75 pairs consisting of 25 input and 50 output pairs.
Although twice as many distribution or output pairs are provided, only half are used at any one time and it is necessary to effect crossconnection between the utilized output pairs and the respective input pairs. Currently, crossconnection is effected manually by installing jumper wires. Whether this is accomplished with quick-connect terminals or with screw terminals, the initial installation is time consuming and must be accomplished by a highly trained installer. When changes or repairs are required, a repairman must be dispatched and an average service call is likely to involve a matter of hours. Moreover, when service personnel change or repair jumper connections, there is not always close adherence to recommended practice and connections are made which eventually reduce the crossconnect box to a jumble of wires, occasionally reaching the point that complete rewiring is required.
Consequently, a considerable overhead is involved in both initial installation and in maintenance of manually operable crossconnection systems as presently used by the telephone companies. An alternative is greatly in demand and the present invention is directed toward providing same.